Issues while running Register-ELBInstanceWithLoadBalancer on powershell

I am trying to add existing Windows Instances to and ELB using below command on powershell :-

Register-ELBInstanceWithLoadBalancer -LoadBalancerName ire798ELB -Instances i-2eb0a88d -Region us-east-1a

But it is giving me below error :-

Register-ELBInstanceWithLoadBalancer : A WebException with status ConnectFailure was thrown. At line:1 char:1 + Register-ELBInstanceWithLoadBalancer -LoadBalancerName ire798ELB -Instances i-2e ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : InvalidOperation: (Amazon.PowerShe...dBalancerCmdlet:RegisterELBInst...dBalancerCmdlet) [Register-ELBInstanceWithLoadBalancer], InvalidOperationException + FullyQualifiedErrorId :

Amazon.Runtime.AmazonServiceException,Amazon.PowerShell.Cmdlets.ELB.RegisterELBInstanceW ithLoadBalancerCmdlet

I tried searching on the net but could not find anything helpful. Can anyone here help me with this please.